Impulse forming and like machines



May 31, 1966 F. BAKHTAR ETAL 3,253,399

IMPULSE FORMING AND LIKE MACHINES Filed Nov. 4, 1964 Z Sheets-Sheet lUnited States Patent 3,253,399 IMPULSE FORMING AND LIKE MACHINES FarhangBaklltar and Stephen Albert Tobias, Birmingham, England, assignors toNational Research Development Corporation, London, England, acorporation of Great Britain Filed Nov. 4, 1964, Ser. No. 408,959 Claimspriority, application Great Britain, Nov. 5, 1963, 43,728/63, 43,729/6314 Claims. (Cl. 6016) This invention relates to impulse formingmachines, in which term is included forging and like machines. In suchmachines, a workpiece is impacted by means of a high energy ram or thelike so as to be shaped or otherwise worked as required. Considerableinterest has arisen in the possibility of deforming material under arate of strain far exceeding the rates achieved in conventionalmanufacturing processes and it has been proposed to achieve this mode ofdeformation by action of a fast-moving ram, which will normally berelatively heavy, the workpiece being deformed to shape, for instance,by reason of the moving ram carrying one part of a die into impulsivecooperation with another part of the die carried by a stationary, oroppositely-moving ram. In known machines, compressed gas, such asnitrogen, is released to propel a piston assembly associated with theram and thereby to provide at least the principal source of energy forthe moving ram(s).

In accordance with the invention, in an impulse forming, forging or likemachine, use is made of the energy of combustion of a fuel or otherrelease of chemical energy of a material, to provide at least part ofthe energy for the initiation of movement and/ or the full movement iceinjecting fuel, such as petrol, into the combustion chamber and a ventvalve 14 which is used on the return stroke of piston 3 for venting thespace in cylinder 4 above the piston, to atmosphere. Three equallyspaced tie rods 15 clamp the closure members 5 and 6 to the cylinder 4,closure member 6 being provided with a number of ports 20, each beingassociated with a relief valve (not shown) which is set to operate at arelatively low pressure.

of the impulsed part of the machine. Thus, in accordance with a featureof the invention, petrol may be ignited in a piston and cylinderarrangement of such a machine and the energy of combustion is impartedto the piston and therefore to the ram. Additionally, compressed gas maybe used to assist in causing movement of the ram, or to continue toenergise the ram.

In a preferred construction of machine according to the invention, thepiston is subject to gaseous pressure, such as front a source ofcompressed air, on one side and to actuating forces due to release ofchemical energy on the other side, the arrangement being such that saidgaseous pressure at least is to be overcome before movement of thepiston is initiated under said actuating forces. The arrangement mayalso be such that some energy for the working stroke of the ram can bederived from the source of gaseous pressure.

The invention has the further object of providing a sequence controldevice for automatic operation of an impulse-forming machine such as hasbeen described above and such as is described in further detail below.

One preferred embodiment of the invention will now be described by wayof example with reference to FIG- URE 1 of the accompanying drawingswhich shows a central section through an impact forging machine. FIGURE2 is a circuit diagram of control suitable for operating such a machine.

In the drawing, a ram 1 is mounted on the end of a sliding shaft 2 whichcarries a piston 3 arranged to slide within a cylinder 4. The cylinder 4has a closure member 5 at the upper end, and a closure member 6 at theother, the shaft 2 sliding in a bearing 7 which has a gaseous seal 8sufficient to support gaseous pressure in the cylinder 4 beneath thepiston 3.

In the upper closure member 5 is formed part of a combustion chamber 9which is completed by a radiative head carrying an inlet valve 11 and anexhaust valve 12. The closure member 5 also carries an atomiser 13 forThe ram 1 carries a tool 16 which co-operates with a lower tool 17supported in a platen 18, the cylinder 4 and its associated parts beingspaced from the platen 18 by means of three equally spaced supports 19.

In operation, taking the sequence. from the situation where the ram 1 isin its impacted position, with the tools 16 and 17 in contact with aworkpiece, compressed air at, say 20 to 40 p.s.i. is introduced throughone of the ports 20 and the piston 3, together with the attached ram 1,rises in its cylinder, the vent valve 14 and the exhaust valve 12 beingopen. When the top of the cylinder is reached, the head of the piston 3seals againnt the underside of closure member 5 under the pressure ofair in the cylinder 4 below the piston.

In order to energise the ram 1, a flow of pre-heated air from a supplyat, say, -250 p.s.i. is led into the combustion chamber 9 through theinlet valve 11, the exhaust valve 12 being left open for an instant toenable any combustion gases remaining from a previous energising stroketo be scavenged from the chamber. After the exhaust valve 12 has beenclosed, further air enters through inlet valve 11, pressurises thechamber and, simultaneously, petrol is sprayed into the chamber throughthe atomiser 13, sufficient time then being allowed for mixing to becomplete in virtue of the swirl imparted to the incoming air.

The vent valve 14 is then closed and the petrol/air mixture is sparkedoff by the sparking plug 21 in the combustion chamber.

Rise of pressure in the chamber due to combustion of the mixture willovercome the back pressure of air in the cylinder 4 below the piston 3;whereupon the piston moves, breaking the seal against the underside ofclosure member 5, and causing high pressure generated in the combustionchamber to be applied to the full area of the piston thereby causing thepiston to accelerate rapidly. The relief valves associated with ports 20operate to prevent an excessive build up of pressure below the pistondue to the energising movement, and in this way the ram 1 is impulsedrapidly to bring the upper tool into contact with the workpiece. Bysuitable choice of the magnitude of piston/cylinder dimensions, theinitial air pressure, the quantity of fuel injected and the setting ofthe relief valves, the piston can be accelerated to any pro-determinedvelocity to suit the characteristics of the forming process to becarried out with the tool applied to the ram.

After impact, the ram is returned to its upper position as described,ready for the next impact stroke.

Modifications to the machine described may be made Within the spirit ofthe invention, as will be understood by those skilled in the art. Forexample, arrangements may be made for air below the piston 3 in cylinder4 to be compressed during the downstroke and for this air to be used tosupply combustion chamber 9, thus reducing the consumption of compressedair from other sources. Further the machine may be made double ended andfiring mechanism provided for both rams, in which case use may possiblybe made of the invention described in the specification accompanyingco-pending patent application No. 408,931 filed on November 4,

1964 in the United States Patent Office.

or control, as used in FIGURE 1, is added in parenthesis to the letterreference.

In FIGURE 2, a relay IV is provided for actuating the inlet valve (11)of the combustion engine and a relay EV for actuating the exhaust valve(12). Relay V is provided for operating a vent valve (14), for ventingthe compression cylinder behind the piston which drives the platen. Thenoperation of the relay BPV controls the back pressure valve to enablethe pressure behind the piston to be maintained at the desired value.

For fuel injection into the combustion chamber, a fuel pump is used, thepump being kept running and a relay FR- is arranged to cause operationof the fuel rack relay FPR, normally in the stop position, to set thefuel line for fuel delivery; in order that the delivery shall besubstantially uniform for each injection, the actual injection iscontrolled by microswitches S1 and S2 (the latter having doublecontacts) which switches respectively close near the commencement of thepumping stroke to operate the fuel rack to inject fuel, and open nearthe end of the stroke to stop injection of fuel. The actual operation ofthe contacts of these switches will be described in more detail blow.Operation of contacts SR1 of start relay SR, by manually closing theswitch labelled START, is arranged to initiate operation of the devicethrough actuation of the start relay slave SRS by closure of contactsSRS/ 1. A stop relay STR is provided to stop the device by opening ofits contacts STR/1 and relay STR is arranged to be energised at somesuitable point in the sequence. A ire-start switch, marked as such, isprovided to enable the device to resume operation. Relay SC is a sparecircuit relay that may be used as required for controlling some otherdesired operation.

In order to actuate the different parts of the gear in the correctsequence, use is made of a switching device comprising threestep-by-step selector switches U51, US2 and USS, such as uni-selectorsused for telephony.

Switch US1 has three banks of contacts USl/ 1, US1/2 and US1/ 3, switchUS2 has four banks, US2/1, US2/2, US2/3 and US2/4 and switch USS hasthree banks US3/1, US3/2 and US3/3. Each of these banks comprises 25contacts uniformly spaced through 360 and these are numbered 0, 1, 2, 312, followed by a repeat series numbered 1 12 in each bank; contact ismade after the second contact 12 is broken. The first bank of eachswitch is arranged so that both series of contacts 1 to 11 are connectedtogether and so that contact 11 of the first series is connected tocontact 1 of the second series; contact 11 of the second series isconnected, through a contact SRS/2/1, SRS/2/2 or SRS/2/3 of the starterrelay slave switch, to one line L1 of a power supply P. Contacts SRS/ 2/1, SRS/2/2 and SRS/2/3 are normally opened for sequence switching but,for example, at the end of a sequence these contacts will be closed andconnection of the first banks of contacts in each selector switch causesthe selector switches to be re-set to a zero position ready for the nextsequence; contact 12 of the second series is connected direct to lineL1. In each second bank of selector switches U51 and US2, the twocontacts 11 are connected together and to the line L1. In the otherbanks of each selector switch, like-numbered contacts are connectedtogether as shown, and are also each connected to one of a row ofsingle-way sockets USl/S, US2/S/ 1, US2/S/2, US3/S/1 or US3/S/2respectively, appropriately numbered 0 to 12 as indicated for socketsUSl/S.

One side of the operating coil for selector switch USI is connected, asis one side of each of the coils for the other selector switches US2 andU83, to line L2 of the power supply and the other side of USl isconnected through contacts STR/1 (normally closed), contacts SRS/1(closed only when the starter relay SR has been energised to operaterelay SRS through closure of contacts SR/l) and through contacts IG/ 1of an impulse generator, to the other line L1 of the power supply. Solong as contacts SRS/1 and STR/1 are closed, the coil of switch US1 isenergised and de-energised respectively each time the impulse generatorcontacts IG/1 are closed and opened; and in this way, the moving contactUSl/C/ 1 is stepped along its row of contacts USl/l at a rate dependentupon the rate of operation of the impulse generator contacts. The movingcontacts US1/Cf2 and US1/C/3 are stepped along their respective banks ofcontacts USl/Z and US1/3 respectively, in step with movement of thecontact USl/C/l. Connection of contact USl/C/ 1 to the commoned contactsof the bank US1/1 during this step-by-step operation, has no effectbecause contacts SRS/2/1 are open normally at this stage.

It will be noted that after 11 such steps, during which connection ismade successively at uniform intervals with the sockets USl/S,connection is made through moving contact US1/C/2 between one side ofthe operating coil of selector switch US2 and the line L1; and, theother side of US2 being connected with line L2, moving contacts US2/C/1,US2/C/2, US2/C/3 and US2/C/4 of the four contact banks of switch US2each makes one step. The fact that contact USZ/C/l now makes contactwith one of the commoned contacts in bank US2/1 has no effect sincecontacts SRS/2/2 are open for this operation. Since the contact US1/C/2immediately moves on to the twelfth contact in bank US1/2, the contactsUS2/C/1, US2/C/2 etc. remain on contact number 1 of their respectivebanks until the next time that the contact US1/C/2 makes contact withthe second of the eleventh contacts, in which case it takes anotherstep. Moving contacts US2/C/3 and US2/C/4 being connected together (infact they may be parts of a double contact arm of the selector switch),it is seen that connection will be made at intervals between likenumbered sockets in rows US2/S/1 and US2/S/ 2 and line L1, theseintervals being twelve times the interval set by the impulse generatorbetween connection of adjacent sockets in row USl/S to the line L1through the moving contact US1/C/3.

A similar stepped connection occurs between likenumbered sockets in rowsU'S3/S/1 and US3/S/2, though the intervals are 12x12 times the basicinterval set by the impulse generator.

It will be seen, therefore, that by connecting, as shown, one side ofeach of the coils of the operating relays for the different parts of thegear to line L12, and the other side of each to an appropriate socket inrow USl/S, the particular coil will be energized each time contactUS1/C/3 moves into contact with the associated contact in bank US1/3; ifthe relays are self-cancelling upon de-energization, then the relayitself will be operated and re-set twice per revolution of contactUS1/C/3. If they are not self-cancelling, but rely upon a secondenergisation of the coil to operate the relay to effect the reversefunction, then it may be necessary to link the L2 'side of the coils toanother of the sockets in row USl/S so as to provide the second(cancelling) operation of the coil at a suitable interval after thefirst. To accommodate operation of a large number of parts of gear, it

may be necessary to provide a series of sockets in parallel with each ofthose in row USl/ S, or alternatively to provide duplicate banks ofcontacts with moving contacts and associated sockets.

If the intervals afforded by the sweeps of contact US1/C/3 are too small(the maximum interval is be tween contacts 0 and 12 in the bank US1/3and that is twelve times the basic interval set by operation of theimpulse generator contacts IG/1) then recourse can be had to use ofsockets US2/S/1 and US2/S/2. As an illustration, operation of the relaycoil for vent valve V(l4) will be taken. Thus, by provision of a jumperJ1 between a socket V/S/l connected to the appropriate side of the relaycoil and a socket in row US2/S/2, and a jumper J2 between the equivalentsocket in row US2/S/1 and a selected socket in row USl/S, provision canbe made for a greater time interval. By plugging jumper J1 into one ofthe sockets in row US3/S/2 and jumper J2 into the equivalent socket ofrow US3/S/1, provision may be made for an even greater time interval.

It -will be seen that, in the latter case by leaving jumper J2 inassociation with the sockets in row USl/S and USZ/S/l and by inserting athird jumper between the appropriate sockets in rows US2/S/2 andUSS/S/l, a finer control of timing is obtainable. Thus if the impulsegenerator. is set to operate at, say one-tenth second intervals, socketsin row USl/S are energised at one-tenth second intervals, sockets inrowsUS2/S/1 and US2/S/2 at roughly unit intervals and sockets in rowsUS3/S/1 and US3/S/2 at roughly ten second intervals. In fact theintervals for the respective steps are one-tenth second, 1.1 seconds and12.1 seconds.

As an example of the use of the switching device to open the vent valve,say 4.3 seconds after the starting switch has been operated, and toclose it after 32.8 seconds, the jumper I la connects sockets V/S/l tothe socket numbered 3 in row US2/S/1 and jumper J2 connects theequivalent socket in row US2/S/2 to socket numbered 7 in row USl/S,these giving delay times of 3.5 seconds and. 0.7 second respectively,which totals 4.3 seconds; and jumper J3 connects socket V/S/2 to thesocket numbered 2 (equivalent to 24.2 seconds elapsing) in row US3/S/2;jumper J4 connects the equivalent socket in row US3/S/1 to the socketnumbered 7 (equivalent to a further 7.7 seconds elapsing) in row US2/S/3and jumper J5 connects the equivalent socket in row USZ/S/l to thesocket numbered 9 (equivalent to a still further 0.9 secondelapsing--giving a total of 32.8 seconds) in row USl/S. The vent valvesolenoid is then pulsed to be energised after 4.3 seconds and furtherpulsed to be de-energised after the requisite interval.

Connections for each of the other relays for operating parts of the gearwill be evident from the above description and from the diagram ofconnections shown in the drawing. If necessary more than one contact maybe in elfect plugged into a single socket by using plug contacts, thatmay plug into the back of another or alternatively further rows ofsockets may be provided these being parallelled with the appropriatesockets in the existing rows.

The circuit for ensuring injection of he correct amount of fuel at theright part of the sequence however, probably needs further detaileddescription. Relay PR is a pulse-operated relay and pulsing uponenergization by the sequence switch results in closing of the slavecontacts FR/l. At a suitable point in the pumping cycle of the fuelinjection pump, the micro-switch S1 is closed by cam-operation from thepump shaft, thereby completing the operating circuit of pulsing relayR1, thus resulting in closure of its slave contacts Rl/l. Closure ofslave contacts R1/1 causes operation of relay R2, the contacts R2/1, R2/2 and R2/ 3 of which thereupon close. Closure of contacts R2/1 completesthe solenoid FPR circuit and actuates the fuel pump rack. to the pre-setinjection position, thus causing injection of the fuel. At a later stagein the rotation of the fuel injection pump, contacts 82/1 and 82/2 ofthe further micro-switch are closed and relays R1 and FR are thereuponpulsed to reset them and to result in relay R2 being de-energised tostop injection of fuel, the fuel injection circuit then being reset forfurther operation.

We claim:

1. An impuse forming machine for automatic operation and having at leastone impulsed part, a piston associated with said impulsed part, acylinder for said piston, an

energy chamber associated with said cylinder, the opening from saidenergy chamber into said cylinder being of substantially smaller crosssectional area than the opera-.

tive area of the said piston, at least one orifice in said chamber forthe introduction of a combustible component for impulsing said piston,means for exhausting gases from said energy chamber, at least one ventin said cylinder towards the opposite end thereof to said energychamber, pressure relief means associated with said vent and means forleading pressurized gas to said opposite end of said cylinder to forcesaid piston into a sealing position against said energy chamber opening.

2. An impulse forming machine as in claim 1 comprising venting' means insaid cylinder for venting the space between said piston and said energychamber during travel of said piston towards said energy chamberopening.

3. An impulse forming machine as claimed in claim ll, means forintroducing compressed gas to the said chamber to move said piston andin consequence said impulsed part towards said chamber so that saidpiston may seal said chamber, means for metering said supply ofcomfoustible compound to said chamber and means for initiatingcombustion of said supply of combustible compound.

4. An impulse forming machine as claimed in claim 3, wherein a sequencecontrol is provided for operation of controls for each of said means inpre-arranged sequence.

5. An impulse forming machine as claimed in claim 4, wherein each saidmeans is provided with electromagnetic actuating mechanism and saidsequence control comprises a plurality of step-by-step selector switcheswith contacts of which are associated connecting members, the firstselector switch being arranged so that its contacts can be sweptrepeatedly at constant intervals and the second and subsequent selectorswitches being arranged so that their contacts can be swept in turnafter a selected number of contacts of the previous selector switch havebeen swept,

and connecting means associated with each said electromagnetic actuatingmechanism whereby connections may be made between said connecting meansand selected individual connecting members to enable actuating circuitsfor said mechanisms to be completed in a given sequence.

6. An impulse forming machine as claimed in claim 5, wherein jumpingconnectors are provided for selective connections between saidconnecting members and said connecting means.

7. An impulse forming machine as claimed in claim 6, wherein saidconnecting members and said connecting means comprise socket means andsaid jumping connectors are provided with plug means for engaging saidsocket means as selected.

8. An impulse forming machine as claimed in claim 5, wherein a pluralityof said connecting members is associated with each contact of at leastone of said selector switches.

9. An impulse forming machine as claimed in claim 5, comprising animpulse generator for energising said first selector switch to cause itscontacts to be swept at a controlled rate.

10. An impulse forming machine having at least one impulsed part, atleast one piston and cylinder arrangement of which the piston isassociated with said impulsed part, an energy chamber, means forsupplying a combustible chemical compound into said chamber, means forintroducing combustion gas into said chamber, means for venting saidchamber, means for introducing compressed gas to the said chamber tomove said piston and in consequence said impulsed part towards saidchamber so that said piston may seal said chamber, means for meteringsaid supply of combustible compound to said chamber and means forinitiating combustion of said supply of combustible compound, wherein asequence control is provided for operation of controls for each of saidmeans in pre-arranged sequence, and wherein each of said means isprovided with electromagnetic actuating mechanism and said sequencecontrol comprises a plurality of step-by-step selector switches withcontacts of which are associated connecting members, the first selectorswitch being arranged so that its contacts can be swept repeatedly atconstant intervals and the second and subsequent selector switches beingarranged so that their contacts can be swept in turn after a selectednumber of contacts of the previous selector switch have been swept, andconnecting means associated with each said electromagnetic actuatingmechanism whereby connections may be made between said connecting meansand selected individual connecting members to enable actuating circuitsfor said mechanisms to be completed in a given sequence.

11. An impulse forming machine as claimed in claim 16 wherein jumpingconnectors are provided for selective connections between saidconnecting members and said connecting means.

12. An impulse forming machine as claimed in claim 11 wherein saidconnecting members and said connecting means comprise socket means andsaid jumping connectors are provided with plug means for engaging saidsocket means as selected.

13. An impulse forming machine as claimed in claim 10 wherein aplurality of said connecting members is associated with each contact ofat least one of said selector switches.

14. An impulse forming machine as claimed in claim 10 comprising animpulse generator for energizing said first selector switch to cause itscontacts to be swept at a controlled rate.

References Cited by the Examiner UNITED STATES PATENTS 2,132,148 10/1938Davis 6026.1 X 2,160,218 5/1939 Kingston et a1 60l6 X 2,402,920 6/1946Seibold 6016 EDGAR W. GEOGHEGAN, Primary Examiner.

1. AN IMPUSE FORMING MACHINE FOR AUTOMATIC OPERATION AND HAVING AT LEASTONE IMPULSED PART, A PISTON ASSOCIATED WITH SAID IMPULSED PART, ACYLINDER FOR SAID PISTON, AN ENERGY CHAMBER ASSOCIATED WITH SAIDCYLINDER, THE OPENING FROM SAID ENERGY CHAMBER INTO SAID CYLINDER BEINGOF SUBSTANTIALLY SMALLER CROSS SECTIONAL AREA THAN THE OPERATIVE AREA OFTHE SAID PISTON, AT LEAST ONE ORIFICE IN SAID CHAMBER FOR THEINTRODUCTION OF A COMBUSTIBLE COMPONENT FOR IMPULSING SAID PISTON, MEANSFOR EXHAUSTING GASES FROM SAID ENERGY CHAMBER, AT LEAST ONE VENT IN SAIDCYLINDER TOWARDS THE OPPOSITE END THEREOF TO SAID ENERGY CHAMBER,PRESSURE RELIEF MEANS ASSOCIATED WITH SAID VENT AND MEANS FOR LEADINGPRESSURIZED GAS TO SAID OPPOSITE END OF SAID CYLINDER TO FORCE SAIDPISTON INTO A SEALING POSITION AGAINST SAID ENERGY CHAMBER OPENING.